Electrical connector and system having contact array interface for engaging contacts at varying centerline spacing

ABSTRACT

An electrical connector for mating with a plurality of contacts separated from one another by a nominal pitch value includes an array of contact surfaces having a first dimension measured in a direction perpendicular to a mating direction between the plurality of contacts and the array of contact surfaces. The first dimension is greater than the nominal pitch value, thereby assuring electrical contact between the contacts and the contact surfaces despite an actual deviation from the nominal pitch.

BACKGROUND OF THE INVENTION

This invention relates generally to electrical connectors, and morespecifically, to electrical connectors which mate with contacts havingvarying centerline spacing due to design variations.

Certain electrical systems, such as, for example, cable to memory boardinterconnection systems, board to board interconnections, and back-planeconnection systems include a large number of interface contacts arrangedin line with one another. The interface contacts are designed to bepositioned relative to one another with a predetermined centerlinespacing between the contacts. The centerline spacing between theinterface contacts, however, may vary in actual practice due tomanufacturing tolerances in constructing and assembling the system, andover a large number of contacts the accumulation of tolerances isproblematic to interfacing the in line contacts with a connectorassembly. Specifically, the tolerances may result in misalignment of thein line contacts with corresponding contacts of the connector, which arealso aligned with one another on a predetermined centerline spacing.Such misalignment of the interface contacts may result in one or more ofthe in line contacts touching the same contact in the connector, therebyshorting the interface contacts to one another. Misalignment of theinterface contacts may also result in some of the contacts not makingelectrical connection with any of the contacts of the connector.

Such problems may be particularly acute in applications having stackedcomponents and a large number of corresponding contacts to mate with aconnector. Such constructions are employed in existing and emergingtechnologies, and are introducing new demands on electrical connectors.For example, fuel cell technology utilizes a large number of conductiveplates arranged in a stack, and it is desirable to monitor a voltage onthe plates during operation. Thus, an electrical contact is provided foreach plate, and the contacts are interfaced with a circuit board whichprocesses the voltage on the plates in the stack for monitoringpurposes. The contacts are fixed to each plate along an end edgethereof, but the width of the plates in the stack is subject tomanufacturing tolerances which may accumulate over a large number of theplates in the stack. Due to the accumulation of tolerances, the actualcenterline spacing of some of the contacts in the plates of the fuelcell stack may vary by up to 100% or more of the nominal centerlinespacing of the plates in the stack. Such variance of the centerlinespacing of the contacts in the stack frustrates the use of conventionalconnectors to connect the contacts of the plates to the circuit board.The varying contact centerlines will either prohibit mating of theconnector to the plate contacts entirely, or cause shorting of thecontacts and/or open circuits between the connector and the contacts ofthe stack.

Conventionally, such tolerance issues have been addressed with tightercontrol of the manufacturing tolerances. However, reducing thetolerances can become cost prohibitive in certain applications.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with an exemplary embodiment, an electrical connector formating with a plurality of contacts separated from one another by anominal pitch value is provided. The connector comprises an array ofcontact surfaces having a first dimension measured in a directionperpendicular to a mating direction between the plurality of contactsand the array of contact surfaces. The first dimension is greater thanthe nominal pitch value, thereby assuring electrical contact between thecontacts and the contact surfaces despite an actual deviation from thenominal pitch.

Optionally, each of the contact surfaces are arranged upon a circuitboard card edge, and the first dimension is approximately twice thenominal pitch value. The circuit board may include opposite first andsecond engagement surfaces with each of the engagement surfacescomprising a plurality of contact pads. The contact pads of the firstengagement surface may be spaced from one another by a distance greaterthan the pitch value, and the contact pads of the second engagementsurface may be spaced from one another by a distance less than the pitchvalue. Alternatively, the connector may comprise a housing and bladecontacts extending from the housing in a two dimensional array.

According to another exemplary embodiment, an electrical system isprovided. The system comprises a plurality of electrical componentsarranged in line with one another and spaced from one another by anominal pitch value, and the components have an edge configured toreceive an electrical contact in more than one position on eachcomponent. A plurality of contacts are selectively engaged to thecomponents, and a connector comprising a plurality of contact surfacesis provided. Each of the contact surfaces is configured to establish anelectrical connection with one of the contacts without shorting thecontacts due to manufacturing tolerances or design variations of thecomponents whereby an actual spacing of the components deviates from thenominal pitch value.

According to still another exemplary embodiment, an electrical systemcomprises a fuel cell stack comprising a plurality of conductive platesarranged in line with one another and spaced from one another by anominal pitch value. Each of the plates have an edge configured toreceive an electrical contact in at least one position on each plate,and the edges define a two dimensional array of contact positions. Aplurality of contacts are provided, and the contacts selectivelypopulate the two dimensional array of contact positions. A connectorcomprises a plurality of contact surfaces, and each of the contactsurfaces is configured to establish an electrical connection with one ofthe contacts without shorting the contacts due to manufacturingtolerances or design variations of the components whereby an actualspacing of the components deviates from the nominal pitch value.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial perspective view of an exemplary electrical systemincluding a connector formed in accordance with an exemplary embodimentof the present invention.

FIG. 2 is another partial perspective view of the system shown in FIG.1.

FIG. 3 is a partial perspective assembly view of a portion of the systemshown in FIGS. 1 and 2.

FIG. 4 is a top plan view of the circuit board shown in FIGS. 1–3.

FIG. 5 illustrates an alternative embodiment of an electrical systemhaving a connector assembly formed in accordance with an exemplaryembodiment of the present invention.

FIG. 6 is a perspective view of a contact assembly for the system shownin FIG. 5.

FIG. 7 is a partial perspective view of another exemplary embodiment ofan electrical system having a connector assembly formed in accordancewith the present invention.

FIG. 8 is a partial perspective view of the system shown in FIG. 8 withthe connector removed.

FIG. 9 is a view similar to FIG. 8 but with parts removed.

FIG. 10 is a front perspective view of the connector shown in FIG. 7.

FIG. 11 is a first assembly view of the system shown in FIG. 7.

FIG. 12 is a second assembly view of the system shown in FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 2 are partial perspective views of an exemplary electricalsystem 100 including an exemplary connector assembly 102 which isadapted for engaging contacts on varying centerlines as explained below.

In an exemplary embodiment, the connector assembly 102 interfaces a fuelcell stack 104 with a monitoring device (not shown) via interface links106 such as wiring harnesses. The interface links 106 are connected, inturn, to a monitoring module 108 which processes signals transmittedfrom the fuel cell 104 through the connector assembly 102 and theinterface links 106. Thus, the monitoring module 108 may be used tomonitor the operation of the fuel cell stack 104 for testing and/ordiagnostic purposes. While the connector assembly 102 is illustrated inthe context of interfacing a fuel cell 104 with a monitoring module 108,it is contemplated that the benefits of the invention accrue to otherapplications of the assembly 102, and the fuel cell 104 is but oneexemplary apparatus which presents issues with respect to contactcenterline spacing which the connector assembly 102 overcomes.Consequently, the description set forth herein is for illustrativepurposes only and is not intended to limit the invention to anyparticular end use or application.

The fuel cell stack 104 is a known unit which reacts a gaseous fuel,such as reformed natural gas, with air to produce electrical power in aknown manner. The fuel cell stack 104 includes a number of conductiveplates 110 which are arranged in a stack. As explained below, platecontacts (not shown in FIG. 1) are selectively attached to some or allof the plates 110, and the plate contacts permit the monitoring module108, via the connector assembly 102, to monitor a voltage oncorresponding plates 110 of the fuel cell 104 during operation. Eachplate 110 in the fuel cell has a predetermined nominal thickness, andthe plates 110 are arranged in the stack with a predetermined nominalspacing value between the plates 110, the sum of which is sometimesreferred to as a nominal pitch value P for the plates 110. That is, thestack of plates 10 is designed to have a reoccurring dimension Pmeasured in a direction perpendicular to the plane of the plates 110from an edge of one plate across the thickness of the plate to the edgeof an adjacent plate. In theory, according to design parameters, theplates 110 are repeated at a uniform distance P in the fuel cell stack.

In reality, each of the plate thicknesses and the spacing of the platesis subject to manufacturing tolerances, and an actual dimension P maydeviate somewhat from the nominal value of the plate thickness and thenominal spacing value for any two adjacent plates in the fuel cell 104.Over a large number of plates 110 in the fuel cell stack, the varianceof dimension P across the plates may accumulate and produce asignificant variance between the theoretical position of a given plate110 in the stack and its actual position in the stack. In a stack havinga large number of plates 110 (e.g., 50 plates), the variance may be upto 100% or more of the nominal value P. As an example, considering anumber of plates n numbered 1 through n, the nth plate in the stackwould theoretically be positioned at a distance n*P from the first platein the stack, but in actual practice, and because of accumulation ofmanufacturing tolerances, the nth plate may be found at a distance inthe range of (n*P+P) to (n*P−P) from the first plate in the stack. Suchvariability in the position of the plates 110 in the stack producesvariability in the contacts connected to the plates 110. Unlike knownconnectors, however, the connector assembly 102 is fully capable ofaccommodating such variance in position of the contacts, as explained indetail below.

In an exemplary embodiment, the connector assembly 102 includes aninsulative (i.e., nonconductive) housing 112 covering the platecontacts. The housing 112 includes an upper portion 114 and a lowerportion 116 each defining a slot 118 and 120, respectively. The slots118 and 120 receive a forward edge 121, 123 of respective circuit boards122 and 124, sometimes referred to as pitch spreading boards. Connectors126 are mounted to the boards 122 and 124 and interface the boards 122and 124 with the interface links 106.

FIG. 2 illustrates the system 100 with the interface links 106 and thelower board 124 removed. The housing 112 of the connector assembly 102includes a number of individual housings 130 collectively forming theslots 118 and 120 which extend between opposite sides 132, 134 of thefuel cell stack. The housings 130 are separately attached to each of theplates 110 in the stack, and thus the position of the housings 130 inthe stack may vary from the nominal spacing value or pitch P asdescribed above. Each housing 130 includes an upper portion 114 and alower portion 116, and one of the upper and lower portions 114 and 116includes a contact extending from a plate 110. The boards 122 and 124(FIG. 1) are insertable into and removable from the slots 118 and 120 toestablish a card edge connection with the plate contacts in the housings130, and ultimately to electrically connect the monitoring module 108 tothe stack of plates 110. Quick connection and disconnection of the platecontacts is therefore provided, and the connector assembly 102accommodates variances in positioning of the contacts due to theaccumulation of manufacturing tolerances in fabricating and spacing theplates 110.

FIG. 3 illustrates the plates 110 of the fuel cell 104 with the housing112 (FIG. 1) removed and the plate contacts 140 extending from end edges142 of the plates 110. In an exemplary embodiment the plates 110 arefabricated in a known molding process to include cavities 144 and 146 inthe end edges 142 wherein and the cavities 144 and 146 are substantiallycentered in the thickness of the plates 110, although it is recognizedthat in alternative embodiments the cavities 144, 146 may otherwise beformed and located in a non-centered position in the plates 110. Thecavities 146 are substantially aligned in a row at a first distance froma top edge 148 of the plates 110, and the cavities 144 are substantiallyaligned in a row at a second distance from the top edge 148. Thus, thecavities 144 and 146 extend in first and second rows on the end edges142 of the plates 110 and define a two dimensional array of cavities144, 146. Each plate 110 includes a cavity 144 and a cavity 146, and thecavities 144 and 146 are similarly shaped and dimensioned so as toreceive a plate contact 140. The plate contacts 140 are thereforepositionable in two locations on each end edge 142, namely in the firstcavity 144 or the second cavity 146. While two rows of cavities 144, 146are illustrated, it is understood that more rows of cavities may beprovided in an alternative embodiment.

As illustrated in FIG. 3, the plate contacts 140 are selectivelypopulated in the two dimensional array of cavities 144 and 146. That is,not all of the cavities 144, 146 includes a plate contact 140. In oneembodiment, and as shown in FIG. 3, the plate contacts 140 are locatedin one or the other of the cavities 144 and 146 in each plate, but notboth. Further, the plate contacts 140 are located in the cavities 144 inevery other plate 110 in the stack, with plate contacts 140 located inthe cavities 146 of the plates therebetween. That is, the plates 110 ofthe stack include an alternative sequence of plates 110 with platecontacts 140 in the cavities 144 and plates 110 with plate contacts 140in the cavities 146. By way of example, considering an n number ofplates numbered 1 through n in the stack, the even numbered plates wouldinclude plate contacts 140 in the cavities 144, and the odd numberedplates would include plate contacts 140 in the cavities 146, or viceversa. Resultantly, the plate contacts 140 are located diagonally fromone another on adjacent plates 110 in the two dimensional array and theplate contacts 140 are staggered from one another in a zigzag patternacross the end edges 142 of the plates 110. The alternating sequence ofplate contacts 140 at different elevations in a two dimensional arrayfacilitates accommodation of accumulated tolerances in a position of theplate contacts 140.

While in the illustrated embodiment a plate contact 140 is provided onevery plate 110 in the fuel cell stack, and hence every plate 110 may bemonitored with the monitoring module (FIG. 1), it is understood thatfewer plate contacts 140 may be provided in an alternative embodimentwherein less than all of the plates 110 are to be monitored by themonitoring module 108. Likewise, in such an embodiment having fewerplate contacts 140, the number of housings 130 (FIG. 2) which protectthe contacts may be accordingly reduced.

In an exemplary embodiment the plate contacts 140 each include a base(not shown in FIG. 3) which is insertable into the cavities 144, 146,and first and second arms 150 and 152 extending from the end edge 142 ofthe plates 110. The arms 150 and 152 are resiliently deflectable whenthe card edges 121, 123 (FIG. 1) of the boards 122 and 124 are insertedtherebetween. Because the cavities 144 and 146 are each in the samelocation in the dimension of the plate thickness (e.g., centered in theplate thickness in an exemplary embodiment), the centerline spacing ofthe plate contacts 140 is subject to the variance in the pitch P betweenadjacent plates 100.

FIG. 4 is a top plan view of an exemplary board 122 including a contactengagement surface 160 and a module engagement surface 162. The contactengagement surface 160 includes a plurality of contact pads 164 alignedalong a card edge 163 which is adapted for insertion between the contactarms 150 and 152 (FIG. 3) of the plate contacts 140. The card edge 163extends for a sufficient length to span a row of plate contacts 140 inthe two dimensional array of plate contacts 140 in the stack of plates110, and each of the contact pads 164 extends for a dimension L₁(measured in a direction perpendicular to a mating direction between theplate contacts 140 and the contact pads 164) along the edge 163 which isgreater than the nominal pitch value P (FIGS. 1 and 2) of the stack ofplates 110. In an exemplary embodiment, L₁ is approximately twice thevalue of P, and therefore when the forward edge 121 (FIG. 2) is receivedin the slot 118 of the housings 130 (FIG. 2) a selected one of the platecontacts 140 (FIG. 3) may vary from its theoretical position based uponthe nominal value of P by up to 100% and still electrically couple theplate contact with the respective contact pad 164 on the contactengagement surface 160. It is understood that greater or lesser ratiosof L₁ and P may be employed in other embodiments as desired or as neededto ensure engagement of plate contacts 140 to the contact engagementsurface 160.

Additionally, because the plate contacts 140 are staggered diagonallyfrom one another on alternating plates 110, plate contacts 140 inadjacent plates 110 in the stack may not engage the same contact pad 164on the contact engagement surface 160 of the board 122. Rather, becauseof the staggered contact in the two dimensional array of plate contacts140, adjacent plate contacts 140 in the stack engage different circuitboards 122, 124, respectively, and shorting of the plate contacts 140 onthe contact engagement surfaces 160 of the boards is avoided even whenthe plate contacts 140 are much closer to one another in the stack thanthe theoretical pitch value P.

The module engagement surface 162 includes a number of contact pads 166which are smaller than the contact pads 164 of the contact engagementsurface 160, and the contact pads 166 have a dimension L₂ (measured in adirection perpendicular to a mating direction between the plate contacts140 and the contact pads 164) which is less than L₁. Thus, while L₁ isgreater than the value of P, L₂ is less than the value of P.Accordingly, the module engagement surface 162 is more compact than thecontact engagement surface 160 and extends for a lesser axial length ofthe board 122 than the contact engagement surface 160. Conductive traces168 interconnect each respective contact pad 164 on the contactengagement surface 160 to a contact pad 166 on the module engagementsurface 162. The smaller module engagement surface 162 is configured forconnection to a wiring harness or standard connector to link the board122 to the monitoring module 108 (FIG. 1). The board 122 may befabricated from known circuit board materials, and the contact pads 164,168 and the conductive traces 168 may be formed according to knownmethods and techniques.

A connector 126 (FIG. 1) may be provided and mounted on the contact pads166, and the connector may include a receptacle for receiving aninterface link 106 such as a wire harness. Alternatively, a card edgeconnector could be employed on the module engagement surface to couplethe board 122 to an interface link 106.

The board 124 (FIG. 1) is constructed similarly to the board 122, andthe contact pads of the board 124 are positioned to engage the platecontacts 140 in the slot 120 (FIGS. 1 and 2) of the housings 130. Eachof the boards 122 and 124 includes contact engagement surfaces havingcontact pads numbering one half of the number of plates 110 in the fuelcell stack, and the respective boards 122, 124 engage the respectiverows of the staggered plate contacts 140 via the card edge slots 118 and120. The board 122 engages the plate contacts 140 in the upper cavities146 of the plates 110, and the board 124 engages the plate contacts 140in the lower cavities 144 of the plates 110. The boards 122 and 124 maybe used separately or in combination to monitor some or all of theplates 110 with the monitoring module 108. It is understood thatadditional boards could be employed with more rows of cavities so thateach board monitors one third, one fourth, etc. of the plates 110 in thestack. By monitoring a predetermined fraction of the plates 110, theperformance of the fuel cell stack may be monitored to varying degrees.

A connector assembly 102 is therefore provided which capablyaccommodates varying centerline spacing of plate contacts 140 whileassuring that all contacts are engaged without shorting any of the platecontacts 140. Additionally, the connector assembly 102 is flexible foruse with different types of components. For example, different boards122 and 124 may be provided having appropriately arranged contactengagement surfaces for devices (e.g., fuel cells) having differentnominal pitch values P for the plates 110. The module engagement surfaceof the boards 122 and 124 may be standardized for universal use amongdifferent types of devices.

FIG. 5 illustrates an alternative embodiment of an electrical system 200including, for example, a fuel cell 104 which is subject to a varyingcenterline pitch P between the plates 110. End edges 142 of the plates110 include cavities 146, and right angle contacts (not shown in FIG. 5)that are selectively mounted within and extend from the cavities 146 toselectively populate the cavities. The plate contacts are situatedwithin housings 202 defining a slot 204 therein, and a circuit board 206is received within the slots 204.

The board 206 includes contact pads 208 aligned along a card edge 207and having a dimension L₃ (measured in a direction perpendicular to amating direction between the plate contacts and the contact pads 208)which is greater than P. The relative dimension of the contact pads 208and the nominal pitch value assures that each of the contact pads 208 isengaged to one of the plate contacts, despite accumulation of tolerancein fabricating and spacing the plates 110. The board 206 may befabricated from known circuit board materials with the contact pads 208formed thereon according to known methods and techniques.

To avoid shorting of the contacts, and as illustrated in FIG. 5, onlyevery other plate 110 (e.g., the odd numbered plates) in the fuel cellstack is provided with a contact. Thus, the board 206 is suited forengaging contacts in some, but not all of the plates 110. Contacts (notshown in FIG. 5) may be provided on the even numbered plates in adifferent location from the odd numbered plates to monitor the evennumbered plates. That is, the plates 110 may include additional cavitieswherein the contacts may be mounted in more than one position on theplates 110.

FIG. 6 is a perspective view of a contact assembly 220 for the system200 shown in FIG. 5. The assembly 220 includes a conductive contact 222having a base 224 insertable into a cavity 146 (FIG. 5) of a plate 110,and a first contact arm 226 and a second contact arm 228 extending fromthe base 224. The arms 226 and 228 are resiliently deflectable when thecard edge 207 (FIG. 5) of the board 206 is inserted therebetween. Thearms 226 and 228 extend at a right angle from the base 224, and aninsulative housing 202 surrounds the contact arms 226 and 228 whiledefining a slot 204 which receives the board 206. The right anglecontacts 222 receive the board 206 in a direction parallel to the endedges 142 of the plates 110, and therefore the system 200 occupies lessroom than the system 100. Additionally, hold-down hardware (not shown)may be required to securely mount the board 206 to the right anglecontacts 222 for monitoring purposes.

The board 206 may include a module engagement surface (not shown) forinterfacing with a monitoring module 108 (FIG. 1). Additionally,circuitry for plate testing and/or monitoring could be directlyincorporated into the board 206.

A connector assembly is therefore provided which capably accommodatesvarying centerline spacing of contacts 222 while assuring that allcontacts are engaged without shorting any of the contacts 222.

FIG. 7 illustrates another embodiment of an electrical system 300including, for example, a fuel cell 104 which is subject to a varyingcenterline pitch P between the plates 110. End edges 142 of the plates110 include cavities (not shown in FIG. 7), and contacts (not shown inFIG. 7) mounted within and extending from the cavities. A connector 302includes an insulative housing 304 having contacts (not shown in FIG. 7)mounted thereto which engage the contacts extending from the plates 110.A monitoring module 305 is coupled to the connector for monitoring theplates 110 in the fuel cell stack.

FIGS. 8 and 9 illustrate multiple contact cavities 310, 312, 314 and 316formed in each end edge 142 of the plates 110. The cavities 310–316 arearranged in four rows, respectively, and each row of cavities 310, 312,314 and 316 is located a different distance from the top edge 148 of theplates 110.

Contacts 320 (FIG. 9) are selectively populated in the two dimensionalarray of cavities 310, 312, 314 and 316. That is, not all of thecavities 310, 312, 314 and 316 includes a contact 320. In oneembodiment, and as shown in FIGS. 8 and 9, the contacts 320 are locatedin only one of the cavities 310, 312, 314 and 316 in each plate.Further, the contacts 320 are located in the respective cavities 310,312, 314 and 316 in every fourth plate 110 in the stack. That is, theplates 110 of the stack include an alternative sequence of four plates110 with contacts 320 in the cavity 316 in the first plate, a contact320 in the cavity 314 in the second plate, a contact 320 in the cavity312 in the third plate, and a contact 320 in the cavity 310 in thefourth plate. Resultantly, the contacts 320 are located in diagonallines in each sequence of four plates 110, and the contacts 320 arestaggered from one another in adjacent plates 110. The alternatingsequence of contacts 320 at different positions or elevations in a twodimensional array facilitates accommodation of accumulated tolerances ina position of the contacts 320. Like the foregoing contacts, thecontacts 320 include a base (not shown) insertable into the cavities310–316 of the plates 110, and a first contact arm and a second contactarm extending from the base. The contact arms are deflectable when amating contact is inserted therebetween.

Insulative housings 322 (FIG. 8) are fitted over each of the contacts320 (FIG. 9) on the plates 110, and the housings 322 define anengagement slot 324. The slots 324 of the housings 322 assist inaligning the connector 302 (FIG. 7) as it is mated with the contacts 320extending from the plates 110.

FIG. 10 illustrates the connector 302 including the housing 304 defininga plurality of contact apertures 306 and a plurality of blade contacts308 extending through the contact apertures 306 with some of the bladecontacts 308 removed for clarity.

The contact apertures 306 and blade contacts 308 are arranged indiagonal lines of a two dimensional array which align with the diagonallines of contacts 320 (FIG. 9). Each blade contact 308 aligns with theengagement slot 324 (FIG. 9) of a housing 322, and also aligns with thecontact 320 within the housing 322 when the connector 302 is installed.In an exemplary embodiment, the housing 304 is molded from a knowninsulative material, such as plastic, and includes a primary alignmentsurface 330 and a secondary alignment surface 332 which is recessedrelative to the primary alignment surface 330. A third surface 334 isprovided which is recessed relative to the second alignment surface 332.The third surface 334 defines a receptacle surrounding many of the bladecontacts 308.

The primary alignment surface 330 includes a first alignment receptacle340 having horizontal and vertical alignment grooves 342 and 344 formedin the outer contours thereof. The vertical grooves 344 provide forinitial alignment with one of the housings 322 of the contacts 320 in avertical direction (i.e., in a direction parallel to arrow A), and thehorizontal grooves 342 provide for initial alignment in a horizontaldirection (i.e., in a direction parallel to arrow B). Thus, the grooves342 and 344 assist in orienting the connector 302 with respect to thefuel cell stack, as illustrated in FIG. 11.

Additionally, the secondary alignment surface 332 includes a secondaryalignment receptacle 346 which provides for secondary alignment withanother of the housings 322 and contact 320 of the fuel cell stack. Thereceptacle 346 may be fitted over another housing 320 to provide furtherpositioning along the vertical axis (i.e., in a direction parallel toarrow A) as illustrated in FIG. 11. Once the alignment receptacles 340and 346 are aligned with respect to the fuel cell 104, the remainingblade contacts 308, housings 322 and contacts 320 are in alignment asshown in FIGS. 11 and 12, and the connector 302 may be fully mated tothe fuel cell 104 by moving the connector in the direction of arrow C.Guidance is therefore provided along two mutually perpendicular axes(i.e., the axes indicated by arrows A and B) to assist in lining up theconnector 302 for mating engagement in the direction of Arrow C.

Each contact blade has a dimension L₄ (FIG. 10, measured in a directionperpendicular to mating direction between the blades 308 and platecontacts 320) which is greater than the nominal pitch value P (FIG. 7)of the plates 110 in the fuel cell stack. The relative dimensions of theblade contacts 308 and the nominal pitch value assures that an outersurface of each of the blade contacts 308 is engaged to one of the platecontacts 320, despite accumulation of tolerance in fabricating andspacing the plates 110. Additionally, staggering the plate contacts 320prevents more than one blade contact 308 from engaging the same platecontact 320 and avoids shorting of adjacent contacts.

A connector assembly 300 is therefore provided which capablyaccommodates varying centerline spacing of contacts 320 while assuringthat all contacts are engaged without shorting any of the contacts 320

While the invention has been described in terms of various specificembodiments, those skilled in the art will recognize that the inventioncan be practiced with modification within the spirit and scope of theclaims.

1. An electrical system comprising: a plurality of electrical componentsarranged in line with one another and spaced from one another by anominal pitch value, said components having an edge configured toreceive an electrical contact in more than one position on each saidcomponent; a plurality of contacts selectively engaged to saidcomponents; and a connector comprising a plurality of contact surfaces,each of said contact surfaces configured to establish an electricalconnection with one of said contacts without shorting said contacts dueto manufacturing tolerances or design variations of the componentswhereby an actual spacing of said components deviates from said nominalpitch value, each of said contact surfaces has a dimension measured in adirection perpendicular to a mating direction between the plurality ofcontacts and the plurality of contact surfaces, said dimension beinggreater than the nominal pitch value.
 2. An electrical system inaccordance with claim 1 wherein said plurality of contacts are arrangedin a two dimensional array.
 3. An electrical system in accordance withclaim 1 wherein said contact surfaces have a dimension measured in adirection perpendicular to a mating direction between the plurality ofcontacts and the plurality of contact surfaces that is approximatelytwice the nominal pitch value.
 4. An electrical system in accordancewith claim 1 wherein said connector comprises a second engagementsurface opposite said contact surfaces, said second engagement surfacecomprising a plurality of contact pads, said contact pads of said secondengagement surface having a length which is less than the nominal pitchvalue.
 5. An electrical system in accordance with claim 1 wherein saidconnector comprises a housing and blade contacts extending from saidhousing.
 6. An electrical system in accordance with claim 1 wherein saidcomponents comprise conductive plates of a fuel cell stack.
 7. Anelectrical system in accordance with claim 1 wherein said contacts arearranged on a fractional number of said components.
 8. An electricalsystem comprising: a plurality of electrical components arranged in linewith one another and spaced from one another by a nominal pitch value,said components having an edge configured to receive an electricalcontact in more than one position on each said component: a plurality ofcontacts selectively engaged to said components; and a connectorcomprising a plurality of contact surfaces, each of said contactsurfaces configured to establish an electrical connection with one ofsaid contacts without shorting said contacts due to manufacturingtolerances or design variations of the components whereby an actualspacing of said components deviates from said nominal pitch value,wherein said connector comprises a circuit board and said contactsurfaces of said connector comprises contact pads.
 9. An electricalsystem comprising: a plurality of electrical components arranged in linewith one another and spaced from one another by a nominal pitch value,said components having an edge configured to receive an electricalcontact in more than one position on each said component; a plurality ofcontacts selectively engaged to said components; and a connectorcomprising a plurality of contact surfaces, each of said contactsurfaces configured to establish an electrical connection with one ofsaid contacts without shorting said contacts due to manufacturingtolerances or design variations of the components whereby an actualspacing of said components deviates from said nominal pitch value,wherein each said electrical component comprises a plurality of cavitieson an edge thereof, said cavities arranged in a two dimensional array.10. An electrical system comprising: a fuel cell stack comprising aplurality of conductive plates arranged in line with one another andspaced from one another by a nominal pitch value, said plates having anedge configured to receive an electrical contact in at least oneposition on each said plate, said edges defining a two dimensional arrayof contact positions; a plurality of contacts, said contacts selectivelypopulating said two dimensional array of contact positions; a connectorcomprising a plurality of contact surfaces, each of said contactsurfaces configured to establish an electrical connection with one ofsaid contacts without shorting said contacts due to manufacturingtolerances or design variations of the components whereby an actualspacing of said components deviates from said nominal pitch value; and ahousing containing each of said contacts, said housing defining a slotconfigured to receive a circuit board edge.
 11. An electrical system inaccordance with claim 10 wherein said connector comprises a secondengagement surface opposite said contact surfaces, said secondengagement surface comprising a plurality of contact pads having adimension measured perpendicular to a mating direction of the contactsand the contact surfaces, said dimension being less than the nominalpitch value.
 12. An electrical system in accordance with claim 10further comprising a housing and blade contacts extending from saidhousing.
 13. An electrical system in accordance with claim 10 whereinsaid contacts are card edge contacts.
 14. An electrical system inaccordance with claim 10 wherein each of said contact surfaces in saidarray has a dimension measured in a direction perpendicular to a matingdirection between the plurality of contacts and the plurality of contactsurfaces, said dimension being greater than the nominal pitch value. 15.An electrical system in accordance with claim 14 wherein said dimensionis approximately twice the nominal pitch value.
 16. An electrical systemin accordance with claim 10 wherein said connector is a circuit boardand said contact surfaces of said connector comprises contact pads. 17.An electrical system in accordance with claim 16, wherein said contactsurfaces are surfaces of a blade contact.